<div dir="ltr"><div>Sorry, but please NAK this submission,</div><div>I found a some typos that I want to clean up.</div><div>A v2 will follow soon ...</div><div> </div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Mar 4, 2022 at 7:29 AM <<a href="mailto:frank.heimes@canonical.com">frank.heimes@canonical.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">BugLink: <a href="https://bugs.launchpad.net/bugs/1962578" rel="noreferrer" target="_blank">https://bugs.launchpad.net/bugs/1962578</a> SRU Justification: [Impact] * The SIGP processing on KVM/s390x is incorrect and not fully conformant to the 'Principles of Operations', the IBM Z architecture definition and documentation. * KVM: SIGP RESTART is reporting a CPU state 'stopped' after SIGP RESTART was issued, while it should report a 'busy' condition until the CPU is really started. * The fix for this consists of three patches: 812de04661c4 "KVM: s390: Clarify SIGP orders versus STOP/RESTART" 435d17955519 "KVM: s390: Add a routine for setting userspace CPU state" 4563bcad46bf "KVM: s390: Simplify SIGP Set Arch handling" whereas 812de04661c4 already landed via upstream stable, hence only two are left and need to be cherry-picked: [Fix] * 67cf68b6a5ccac8bc7dfef0a220b59af4c83fd2c 67cf68b6a5cc "KVM: s390: Add a routine for setting userspace CPU state" * 8eeba194a32e0f50329354a696baaa2e3d9accc5 8eeba194a32e "KVM: s390: Simplify SIGP Set Arch handling" [Test Case] * Install an LPAR on IBM Z (z13+) or LinuxONE (Emperor / Rockhopper) with Ubuntu Server 20.04 using kernel standard kernel 5.4. * Setup this LPAR as QEMU/KVM host and a focal VM as guest. * The test itself is the following unit test: <a href="https://lore.kernel.org/r/20220303210425.1693486-1-farman@linux.ibm.com/" rel="noreferrer" target="_blank">https://lore.kernel.org/r/20220303210425.1693486-1-farman@linux.ibm.com/</a> * The test and verification will be done by the IBM Z team. [Where problems could occur] <this is pretty high level and generic, anything more specific to add?> * A broken patch could harm KVM ioctl on s390x or the (virtual) CPU state control in general. * The SIGP handing (on s390x) can become broken, which could lead to incorrect (virtual) CPU states. * In worst case KVM can become broken on s390x entirely. * The modified code is all s390x specific QEMU/KVM code, no common code is touched. [Other] * The two remaing patches are upstream since 5.16, the first one already landed in 5.4 via upstream stable bug LP#1959701 and in 5.13 via upstream stable bug LP#1960861. * The patches already landed in jammy (master-next) based on LP#1959735, hence only SRU to impish and focal is needed. * This patches got discussed here: <a href="https://lore.kernel.org/all/20211008203112.1979843-2-farman@linux.ibm.com/" rel="noreferrer" target="_blank">https://lore.kernel.org/all/20211008203112.1979843-2-farman@linux.ibm.com/</a> * This not only fixes the SIGP processing, but is also important in terms of long term maintainability. Eric Farman (2): KVM: s390: Simplify SIGP Set Arch handling KVM: s390: Add a routine for setting userspace CPU state arch/s390/kvm/kvm-s390.c | 6 +++--- arch/s390/kvm/kvm-s390.h | 9 +++++++++ arch/s390/kvm/sigp.c | 14 +------------- 3 files changed, 13 insertions(+), 16 deletions(-) -- 2.25.1 -- kernel-team mailing list <a href="mailto:kernel-team@lists.ubuntu.com" target="_blank">kernel-team@lists.ubuntu.com</a> <a href="https://lists.ubuntu.com/mailman/listinfo/kernel-team" rel="noreferrer" target="_blank">https://lists.ubuntu.com/mailman/listinfo/kernel-team</a> </blockquote></div></div>